BATOCRINID&. 391 
lower face is slightly excavated for the reception of the column. Radials 
large, twice as wide as long. First costals by one half narrower and shorter 
than the radials, quadrangular; the second pentangular, wider than the 
first. Distichals two ; the upper one axillary, giving off from each side two 
large palmars, which support the arms. Arms twenty, four to each ray ; 
long, incurving and biserial; at their bases they are somewhat angular on 
the back, but at an inch from the calyx they gradually flatten and increase 
in width, reaching at half length their greatest diameter —8 to 9 mm. — 
which they retain a short distance, and become reduced to 5 or 6 mm. 
at the tips. The sides of the arms are knife-like, with dentate edges, the 
median portions considerably thickest. The arm plates increase in length 
upward from 1 to 3 mm. Interradials three, in two rows; the anal plate is 
succeeded by three and two pieces. Ventral disk high, conical, passing grad- 
ually into the ventral tube, which is rather long and stout. The plates of 
the tegmen, including those of the ventral tube, are strongly tuberculous. 
Horizon and Locality. — Keokuk group ; Indian creek, Montgomery Co., 
Ind., and Canton, Ind. 
Lypes in the collection of Wachsmuth and Springer. 
Eretmocrinus minor W. and Sp. (nov. spec.). 
Plate XXXVI. Figs. 10a, b. 
Calyx subpyriform, higher than wide. Dorsal cup constricted at the basi- 
radial sutures, thence expanding moderately with straight sides to the arm 
bases. Ventral disk semiovoid, slightly inflated at the anterior side, the pos- 
terior side somewhat depressed. The plates of the dorsal cup perfectly flat 
and smooth, those of the tegmen a little convex. 
Base broadly truncate, moderately high, slightly expanding downward, 
the lower edges sharply angular, the bottom flat and hexangular. Radials 
nearly twice as wide as long, the upper face concave. Costals comparatively 
large; the first quadrangular, a little shorter and considerably narrower than 
the radials, their upper and lower faces convex; the second wider than the 
first and heptangular, the sides abutting against the second row of inter- 
brachials. Distichals three in the anterior ray, supporting two arms; in the 
other rays one division has three distichals, the other but two, of which the 
upper one is axillary, giving off a palmar from each side. Occasionally one 
or both antero-lateral rays have four arms in place of three. Arm facets 
